Needle-bar mechanism for sewing machines



Feb; 25. 1930. G. s. GATCHELL NEEDLE BAR MECHANISM FOR SEWING MACHINES 2 Sheets-Shet 1 Filed March 22, 1928,

INV ENTOR Qe aye Gale/2d! BY ATTORNEY Feb. 25, 1930. G. s. GATCHELL 8,

' NEEDLE BAR MECHANISM FOR SEWING MACHINES I I Filed' March 22, 1928 Z Sheets-She et 2 6 v a I 7////// y/////////////////////JV//// I JV I. n gw/ iii q I INVENTOR I J v w|TNEssE% BY v ATTORNEY fi 'Patented Feb. 25, 1930 ES A ENT oFi-" IC E the'usual feed-mechanism. f

GEoRGE s. GA'r GRELL, 0F ROSELLE PARK, NEW JERSEY, ASSJlGNOR 'r o THEsINGER MANUFACTURING COMPANY, OF ELIZABETH,;I\TEW; JERSEY, A CORPORATION or NEW .JERsEY 1 ERDLE-R R Ec AN sM EoR' SEWING MAG INE's "'lipplication iiliadMarchBZ, 1928. Serial No. 263,628.

This inventionrelates to sewing machines, more particularly of'the type in. whlch asingle loop-taker cooperates with'a plurality I of needles, and has for an object to secure an improved relative timing between the needles and loop-taker, together with an increased lift or clearance of the lower needle above the work and'an increased timeperiod that the lower needle is out of the work, during which time the work is moved a stitch-length by To the attainment of the ends in view, provision is made vfor-the differential actuation of the needles, preferably by providing a plurality of needle-bars, one for each needle, and by actuating theineedle-bars by separate link-connections with 'cranks'of different radii on a crank-arm. carried. by" a needle-bar operating rock-shaft. When the needles are at the lower end of the stroke,

their eyes stand at different elevations, the

eye of the needle more remote from the looptaker being at the lower elevation. The working centers of the needle-bar operating rock shaft and the link-connection with the needlebar carrying the lower needle preferably come substantially into alignment, producing a dwell in the lower needle at the end of its 1 down-stroke. When the needles rise, the lower needle rises more slowly at first'as the loop-taker seizes a loop from the'higher needle. The upmotion of the lower needle is then accelerated so that its eye will rise to the proper height to form its loop by the time the looper-beak crosses the space between the needles. 'The" acceleration of the lower needle relative to, the other needle is continued after the needlei loops are seized, to hasten the time when the lower needle-point is lifted clear of the'work; making it possible to begin the feed off'the Work at an earlier time and continue it over a longer portion of the cycle than heretofore possible in a.multiple-needle,- singlelooper machine. By, the time the needles reach the end-of the their lip-stroke, the accelerated :motion of the lower needle has carried it to the same height as'the other needle; giving 7 a maximum clearance between the needlepoints and the work and enabling the machine In the accompanying drawings,

' F ig. 3 is a view of the Fig. ,9 is a perspective view to sew work of maximum thickness. On the down-stroke of the needles, the lower. needle descends more rapidly than the other-needle and reaches-the looper in time, to properly Fig. is

enter the looper-thread loop.

front, end elevation of the bracket-arm and cylinderbed of'a sewing machine embodying the invention; the needles being down.

Fig. 2 is a similar view with the needles up. needles and looper at the time the latter is seizing a loop from the I tive views. "of the two needle-bars, disas-J sembled, and Fig. 12'isa diagrammatic'view showing the relative differential movements ofthe needles. I I .7

In the preferred embodiment of the inven-u free end of the usual overhanging'bracket-i arm '2 of a sewing machine, below which 75. tion'illustrated, 1 represents the head atthe bracket-arm is located the cylinderbed 3.

Journaled within andv lengthwise of the bracket-arm is the needle-bar operating rockshaft 4 driven by any suitablemechanism such, for example, as thatdisclosed in the patent to Gatchell, No. 1,319,469 of October 21, 1919, which also discloses suitable mecha-' looper-shaft'i'5 carrying the-looper 6.

s5:- nismlfon'operating the sliding and rocking J ournaled in. bearings 7 in the'hea'd.

the needle-bar 8 carrying the needle 9L1 The-1 needle-bar 8 is formeolin one side with a I groove 10, Fig. 10, in which is slidably fitted a secondneedlebar 11 carrying the needle 12. Glamped to the needle-ban 8 is the split sleeve 13 to which'is fixed-thestud-pin 14 embraced by one endof' a link 15conne'cted at its opposite end to the crank pin '16 onthe arm17"fix ed to the rock-shaft 4. Secured 'to'the needle-bar'll by means of the screw 1 18 is the sleeve 19'to which isIfiXed the stud,-

pin 20 embraced-by one end of-alink 21 con-" 19. .7 5'

nected at its opposite end to a crank-pin 22 carried by the arm 17 and offset from the crank 16.

The crank-pin 22 which actuates the needle-bar 11 carrying the lower needle .12 is set at a greater distance from *the axis of the shaft 4: than the crankpin16, and the said crank-pinssubtend an angle afFig. 2, of about 12. WVhen the needle-barscare down, the crank-pin 22 moves substantially to a pointin alignment with the axes of the,

shaft 4 and stud-pin 20, whereby a dwell is imparted to the lower needle 12.

When the needles are down, theneedlelQ stands lower than the needle 9 but need not stand as low as in prior machines where both needles are fixed to the same needle-bani During the early part of the up-stroke of the needles, the needle 9 rises more rapidly than the needle 12 and reaches the position-shown in Fig. 3 in time for its:loop to be seized by the beak of the advancing looper 6. By the.

time the looper beak has crossed the space between the needles, the lower needle 12 has risen to the proper height for formation of its loop for seizure by the looper. Both needles rise at substantially the same speed as the looper is crossing the space between theneedles and their diflerenc e in elevation during this time is substantially constant.

After the looper has seized the needleloops, the Lip-motion of theneedle 12 relative to the. needle 9 is accelerated to hasten/the time that the needle 12 is lifted clearof the work for the work-feeding operation. This acceleration of the up-motion of the needle 12 relativeto the needle 9 is continued until the needles reach the limit of their up-stroke, at which time the needle-points stand at substantially the sameelevation above the work.

' This provision secures a maximum time for the accomplishment of the feed of the work and enables the machine to sew work vof maximum thickness with a minimum needlebar stroke. r Having thus set forth the nature of the invention, what I claim herein is :-v

1. In a sewing machine, the combination with aloop-taker, and a pluralityof needlebars each carrying aneedle, of a needle-baroperating rock-shaft, a plurality of cranks on said rock-shaft, and a link-connection between eachof said cranks and a respective one of said needle-bars; the radii of said cranks forming an acuteangle.

QJIn a sewing'machine, the combination witha loop-taker, and a plurality of'needlebars each carrying aneedle, of a needle-bar operating rock-shaft, a plurality of cranks on said rock-shaft, and a link-connection be tween each of said cranks and a respective one of said needle-bars; the radii of said cranks forming an acute angle and being of difierent lengths, the longer crank being condle-bars simultaneously in the same direction but at different speeds.

In testimony whereof, I have signed my name to this specification.

ononen s. VGATCHELL. 

